Final answer:
Rounding in liquid medicines and injections is important for accurate and precise dosing. The precision and accuracy of dispensers should be evaluated, and rounding rules should be followed to ensure consistent dosing.
Step-by-step explanation:
In the context of liquid medicines and injections, rounding is often necessary to ensure accurate and precise dosing. Rounding rules usually depend on the number of significant figures required. In this case, the quality control chemist is evaluating the accuracy and precision of three different machines for dispensing cough syrup. Dispenser #1 is precise but not accurate, dispenser #2 has improved accuracy but worse precision, and dispenser #3 is both accurate and precise.
When rounding in scientific calculations, the general rule is to round to the same number of significant figures as the least precise value in the calculation. This ensures that the result is not more precise than the original data. For multiplication and division, the result should be rounded to the same number of digits as the number with the fewest significant figures.
Therefore, in the case of liquid medicines and injections, precision and accuracy are important factors in determining the reliability of a dispenser, and rounding rules should be followed to maintain consistent dosing.